U.S. patent application number 13/253371 was filed with the patent office on 2012-04-05 for method of allocating radio resource and transmitting data.
This patent application is currently assigned to ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE. Invention is credited to Hyun Kyu CHUNG, Seung Eun HONG, Yong Sun KIM, Woo Yong LEE.
Application Number | 20120082142 13/253371 |
Document ID | / |
Family ID | 45889786 |
Filed Date | 2012-04-05 |
United States Patent
Application |
20120082142 |
Kind Code |
A1 |
KIM; Yong Sun ; et
al. |
April 5, 2012 |
METHOD OF ALLOCATING RADIO RESOURCE AND TRANSMITTING DATA
Abstract
Provided is a data transmission method. The data transmission
method may limit a use authorization for a contention time period
so that a portion of data transmission devices among a plurality of
data transmission devices may transmit data during the contention
time period.
Inventors: |
KIM; Yong Sun; (Daejeon,
KR) ; HONG; Seung Eun; (Daejeon, KR) ; LEE;
Woo Yong; (Daejeon, KR) ; CHUNG; Hyun Kyu;
(Daejeon, KR) |
Assignee: |
ELECTRONICS AND TELECOMMUNICATIONS
RESEARCH INSTITUTE
Daejeon
KR
|
Family ID: |
45889786 |
Appl. No.: |
13/253371 |
Filed: |
October 5, 2011 |
Current U.S.
Class: |
370/336 |
Current CPC
Class: |
H04W 74/02 20130101;
H04W 74/0841 20130101; H04W 72/10 20130101; H04W 74/08 20130101;
H04W 84/12 20130101 |
Class at
Publication: |
370/336 |
International
Class: |
H04J 3/00 20060101
H04J003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 5, 2010 |
KR |
10-2010-0096649 |
Aug 24, 2011 |
KR |
10-2011-0084409 |
Claims
1. A method of transmitting data, the method comprising: setting an
order of priority for a contention time period; receiving, from a
resource allocation device, a use authorization for the contention
time period; determining whether to use the contention time period
by comparing the order of priority and the use authorization; and
transmitting data to a data reception device during the contention
time period based on the determination.
2. The method of claim 1, wherein the order of priority is set
based on a characteristic of the data.
3. The method of claim 2, wherein, when the data corresponds to
audio data, the order of priority is set to a relatively high
value.
4. The method of claim 1, further comprising: receiving, from the
resource allocation device, an order of priority for the contention
time period, wherein the setting comprises setting an order of
priority for the contention time period according to the received
order of priority.
5. The method of claim 1, further comprising: determining whether a
reception acknowledgement (ACK) message is received for the
transmitted data, and retransmitting the data when the reception
ACK message is not received.
6. The method of claim 1, wherein the determining comprises
determining to use the contention time period when the order of
priority is greater than or equal to the use authorization.
7. The method of claim 1, further comprising: waiting during a
predetermined period of time from a starting time of the contention
time period; and cancelling the transmitting of data when second
data transmitted by a data transmission device is received during
the predetermined period of time.
8. A method of allocating a resource, the method comprising:
determining a contention time period; setting a use authorization
for the determined contention time period; and transmitting the use
authorization to a plurality of data transmission devices in which
an order of priority for the contention time period is set, wherein
the use authorization is compared to the order of priority of each
of the plurality of data transmission devices, and the plurality of
data transmission devices transmits data to a data reception
terminal during the contention time period based on a result of the
comparison.
9. The method of claim 8, wherein the order of priority of each of
the plurality of data transmission devices is set based on a
characteristic of the data.
10. The method of claim 9, wherein, when the data corresponds to
audio data, the order of priority of each of the plurality of data
transmission devices is set to a relatively high value.
11. The method of claim 8, further comprising: setting an order of
priority for the contention time period of each of the plurality of
data transmission devices; and transmitting the set order of
priority to each of the plurality of data transmission devices.
12. The method of claim 8, wherein the plurality of data
transmission devices transmits the data when the order of priority
is greater than or equal to the use authorization.
13. A method of receiving data, the method comprising: comparing a
use authorization set for a contention time period and an order of
priority set for a data transmission device; and receiving
transmitted data according to a result of the comparison from the
data transmission device during the contention time period.
14. The method of claim 13, wherein the order of priority is set
based on a characteristic of the data.
15. The method of claim 14, wherein, when the data corresponds to
audio data, the order of priority is set to a relatively high
value.
16. The method of claim 13, further comprising: transmitting a
reception acknowledgement (ACK) message for the received data to
the data transmission device.
17. The method of claim 13, wherein the contention time period is
determined to be used when the order of priority is greater than or
equal to the use authorization.
18. The method of claim 13, further comprising: re-receiving, after
a predetermined period of time, from one of a plurality of data
transmission devices, data transmitted by the one of the plurality
of data transmission devices, wherein the receiving of data
comprises receiving data from each of the plurality of data
transmission devices.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Korean Patent
Applications No. 10-2010-0096649, filed on Oct. 5, 2010 and No.
10-2011-0084409, filed on Aug. 24, 2011, in the Korean Intellectual
Property Office, the disclosures of which are incorporated herein
by reference.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention relates to a method of transmitting
data in a wireless local area network (WLAN) or wireless personal
area network (WPAN) environment, and more particularly, to a method
of allocating a radio resource for preventing a collision of data
transmitted by a plurality of data transmission devices, and to a
method of transmitting data using the allocated radio resource.
[0004] 2. Description of the Related Art
[0005] A conventional network such as a wireless local area network
(WLAN) or a wireless personal area network (WPAN) may allocate a
predetermined radio resource to a predetermined data transmission
device, or may use a contention based transmission scheme in which
a predetermined data transmission device transmits data without
sharing a predetermined radio resource.
[0006] In the contention based transmission scheme, a plurality of
data transmission devices may share a radio resource, and a data
transmission device having data to be transmitted may transmit the
data using the radio resource. In this instance, when the plurality
of data transmission devices transmits data using the same radio
resource, a data reception device may not receive data from any of
the plurality of data transmission devices, which may correspond to
a collision of data transmitted by each data transmission device.
The collision may be an issue to be prevented in the contention
based transmission scheme.
SUMMARY
[0007] An aspect of the present invention provides a method of
allocating a resource that may reduce a data collision among a
plurality of data transmission devices in a contention time
period.
[0008] Another aspect of the present invention also provides a
method of transmitting data that may enhance a possibility of
succeeding in transmitting data.
[0009] According to an aspect of the present invention, there is
provided a method of transmitting data, the method including
setting an order of priority for a contention time period,
receiving, from a resource allocation device, a use authorization
for the contention time period, determining whether to use the
contention time period by comparing the order of priority and the
use authorization, and transmitting data to a data reception device
during the contention time period based on the determination.
[0010] According to another aspect of the present invention, there
is provided a method of allocating a resource, the method including
determining a contention time period, setting a use authorization
for the determined contention time period, and transmitting the use
authorization to a plurality of data transmission devices in which
an order of priority for the contention time period is set, wherein
the use authorization is compared to the order of priority of each
of the plurality of data transmission devices, and the plurality of
data transmission devices transmits data to a data reception
terminal during the contention time period based on a result of the
comparison.
[0011] According to still another aspect of the present invention,
there is provided a method of receiving data, the method including
comparing a use authorization set for a contention time period and
an order of priority set for a data transmission device, and
receiving transmitted data according to a result of the comparison
from the data transmission device during the contention time
period.
[0012] According embodiments of the present invention, it is
possible to reduce a data collision among a plurality of data
transmission devices in a contention time period.
[0013] According embodiments of the present invention, it is
possible to enhance a possibility of succeeding in transmitting
data.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] These and/or other aspects, features, and advantages of the
invention will become apparent and more readily appreciated from
the following description of exemplary embodiments, taken in
conjunction with the accompanying drawings of which:
[0015] FIG. 1 is a diagram illustrating a method of transmitting
data according to embodiments of the present invention;
[0016] FIG. 2 is a flowchart illustrating a method of transmitting
data according to embodiments of the present invention;
[0017] FIG. 3 is a diagram illustrating a beacon interval structure
according to embodiments of the present invention;
[0018] FIG. 4 is a diagram illustrating a scheduling information
element according to embodiments of the present invention;
[0019] FIG. 5 is a diagram illustrating an allocation of a
contention time period according to embodiments of the present
invention;
[0020] FIG. 6 is a diagram illustrating a traffic mapping according
to embodiments of the present invention;
[0021] FIG. 7 is a flowchart illustrating a method of transmitting
data according to embodiments of the present invention;
[0022] FIG. 8 is a flowchart illustrating a method of allocating a
resource according to embodiments of the present invention; and
[0023] FIG. 9 is a flowchart illustrating a method of receiving
data according to embodiments of the present invention.
DETAILED DESCRIPTION
[0024] Reference will now be made in detail to exemplary
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings, wherein like reference
numerals refer to the like elements throughout. Exemplary
embodiments are described below to explain the present invention by
referring to the figures.
[0025] FIG. 1 is a diagram illustrating a method of transmitting
data according to embodiments of the present invention.
[0026] A resource allocation device 110 may allocate a
predetermined radio resource to each of data transmission devices
120 and 140 so that each of the data transmission devices 120 and
140 may transmit data. Hereinafter, the data transmission device
120 may be referred to as a first data transmission device 120, and
the data transmission device 140 may be referred to as a second
data transmission device 140 for convenience of description. In
response to a predetermined radio resource allocated to a
predetermined data transmission device, for example, the first data
transmission device 120 or the second data transmission device 140,
the predetermined data transmission device may transmit data using
the allocated radio resource. Thus, a collision may not occur
between data transmitted by the first data transmission device 120
and data transmitted by the second data transmission device 140.
Herein, the transmission of data using an allocated radio resource
may refer to as a non-contention based data transmission.
[0027] According embodiments of the present invention, the resource
allocation device 110 may allocate a common radio resource that may
be used for the data transmission devices 120 and 140 to transmit
data. When each of the data transmission devices 120 and 140 has
data to be transmitted, each of the data transmission devices 120
and 140 may transmit the data using the common radio resource.
[0028] In the contention based data transmission, when a single
data transmission device transmits data, the data may be
transmitted successfully. However, when a plurality of data
transmission devices, for example, the data transmission devices
120 and 140 transmit data, a data collision may occur, and a data
reception device 130 may be unsuccessful in receiving any data.
[0029] To prevent the data collision, each of the data transmission
devices 120 and 140 may wait during a predetermined period of time,
within a time period for transmitting data. The first data
transmission device 120 may verify whether the second data
transmission device 140 transmits data for the predetermined period
of time. When the first data transmission device 120 fails to
receive data from the second data transmission device 140 during
the predetermined period of time, the first data transmission
device 120 may determine the second data transmission device 140
does not transmit data during the period of time for transmitting
data, and may transmit data of the first data transmission device
120. As such, a collision of data transmitted by each of the data
transmission devices 120 and 140 may be significantly reduced.
[0030] According embodiments of the present invention, each of the
data transmission devices 120 and 140 may transmit and receive data
using an array antenna or a directional antenna including a
plurality of antennas. In this instance, the data transmission
devices 120 and 140 may transmit data in a predetermined direction,
or receive data from a predetermined direction.
[0031] FIG. 1 illustrates that the second data transmission device
140 includes an array antenna. Data transmitted by the second data
transmission device 140 may be transmitted to a first data
reception device 150 and the second data reception device 130. The
second data transmission device 140 may concentrate a transmission
of data in a direction of the second data reception device 130 and
thus, may not receive data transmitted from the first data
transmission device 120. Thus, the second data transmission device
140 may not verify whether the first data transmission device 120
transmits data, and may transmit data to the second data reception
device 130 using the same radio resource as the first data
transmission device 120. In this instance, the second data
reception device 130 may receive data from neither the first data
transmission device 120 nor the second data transmission device
140.
[0032] According embodiments of the present invention, the resource
allocation device 110 may set a use authorization for a radio
resource. The resource allocation device 110 may transmit the set
use authorization to each of the data transmission devices 120 and
140. Each of the data transmission devices 120 and 140 may set an
order of priority for a radio resource. That is, the order of
priority may be individually set for each of the data transmission
devices 120 and 140 and thus, the first data transmission device
120 may have a relatively high order of priority, and the second
data transmission device 140 may have a relatively low order of
priority. Each of the data transmission devices 120 and 140 may
compare a set use authorization and an order of priority of each of
the data transmission devices 120 and 140 for a radio resource.
[0033] When an order of priority of each of the data transmission
devices 120 and 140 exceeds a set use authorization, each of the
data transmission devices 120 and 140 may transmit data using the
corresponding radio resource. When an order of priority of the
first data transmission device 120 exceeds a use authorization set
for a radio resource, and an order of priority of the second data
transmission device 140 is less than a use authorization set for
the radio resource, the first data transmission device 120 may
transmit data.
[0034] A portion of data transmission devices may transmit data
based on a result of comparing an order of priority of each of the
data transmission devices 120 and 140 and a use authorization set
for a radio resource. Accordingly, a possibility of a collision of
data transmitted by data transmission devices may be significantly
reduced.
[0035] FIG. 2 is a flowchart illustrating a method of transmitting
data according to embodiments of the present invention.
[0036] In operation 240, a data transmission device 220 sets an
order of priority for a common radio resource. According
embodiments of the present invention, the data transmission device
220 may set the order of priority based on a characteristic of data
to be transmitted by the data transmission device 220. For example,
when the data to be transmitted corresponds to audio data, the data
transmission device 220 may set a relatively high order of
priority. When the data to be transmitted does not correspond to
audio data, the data transmission device 220 may set a relatively
low order of priority.
[0037] In operation 250, a resource allocation device 210 may set
an order of priority for a contention time period. According to
embodiments of the present invention, the resource allocation
device 210 may set a use authorization for the contention time
period based on a number of data transmission devices desiring to
use the contention time period. For example, when the number of
data transmission devices desiring to use the contention time
period is relatively great, the resource allocation device 210 may
set a use authorization for the contention time period to a
relatively high value. The resource allocation device 210 may
transmit the use authorization for the contention time period to
the data transmission device 220.
[0038] In operation 260, the data transmission device 220 may
determine whether to use the contention time period by comparing
the order of priority for the contention time period and the use
authorization of the data transmission device 220. In this
instance, using the contention time period may correspond to
transmitting data by the data transmission device 220 to a data
reception device 230.
[0039] When the contention time period is determined to be used in
operation 260, the data transmission device 220 may transmit data
to the data reception device 230 in operation 270.
[0040] When a single data transmission device, for example, the
data transmission device 220 transmits data in operation 270, the
data reception device 230 may succeed in receiving data, and
transmit a reception acknowledgement (ACK) message to the data
transmission device 220 in operation 280.
[0041] However, when a plurality of data transmission devices,
including the data transmission device 220, transmits data in
operation 270, the data reception device 230 may fail to receive
data from any of the plurality of data transmission devices since
data transmitted by each of the plurality of data transmission
devices may collide. Thus, the data reception device 230 may not
transmit the reception ACK message.
[0042] FIG. 3 is a diagram illustrating a beacon interval structure
according to embodiments of the present invention.
[0043] A beacon interval (BI) 310 may include a beacon time (BT)
330, an associated beamforming training (A-BFT) 340, an
announcement time (AT) 350, and a data transfer time (DTT) 320. The
BT 330, the A-BFT 340, the AT 350, and the like correspond to time
periods for transmitting control information, for transmitting
data, and the DTT 320 corresponds to a time period for transmitting
data.
[0044] According to embodiments of the present invention, the DTT
320 may include contention-based periods (CBP1 and CBP2) 360 and
361, and service periods (SP1 and SP2) 370 and 371. The CBP1 and
the CBP2 each correspond to a time period during which each data
transmission device transmits data in a contention-based
transmission scheme, and hereinafter is referred to as a contention
time period for conciseness in this specification. The SP1 and the
SP2 each correspond to a time period during which each data
transmission device transmits data using a radio resource uniquely
allocated to each data transmission device.
[0045] Referring to FIG. 3, the CBP1 360 and the CBP2 361 may be
allocated within a single BI 310. When a plurality of data
transmission devices transmits data during the CBP1 360 and the
CBP2 361, a data collision may be likely to occur during the CBP1
360 and the CBP2 361.
[0046] FIG. 4 is a diagram illustrating a scheduling information
element according to embodiments of the present invention. As
described in the foregoing, to reduce a possibility of a data
collision in a contention time period, a portion of data
transmission devices among a plurality of data transmission devices
may transmit data in the contention time period.
[0047] According to embodiments of the present invention, a
resource allocation device may allow a portion of data transmission
devices to use a contention time period by setting a use
authorization for each contention time period.
[0048] The resource allocation device may use scheduling
information 410 illustrated in FIG. 4 to transmit, to a data
transmission device, information regarding whether a contention
time period is set within a BI and a use authorization for the set
contention time period.
[0049] The scheduling information 410 may include an allocation
information element 411. An allocation information element 420
further illustrates the allocation information element 411 included
in the scheduling information 410. The allocation information
element 420 may include allocation control information 421.
Allocation control information 430 further illustrates the
allocation control information 421 included in the allocation
information element 420. The allocation control information 430 may
include traffic identification (TID) information 431.
[0050] Referring to FIG. 4, in response to allocation type
information being set to "0," the corresponding scheduling period
may set to a non-contention time period, and a predetermined radio
resource may be allocated to each data transmission device. A data
transmission device may transmit data without a collision using an
allocated radio resource. In this instance, a traffic category
value or a traffic stream value may be allocated to the TID
information 431, and data transmitted by each data transmission
device may be identified using the TID information 431.
[0051] According to embodiments of the present invention, in
response to allocation type information being set to "1," the
corresponding scheduling period may be set to a contention time
period. In this instance, the resource allocation device may
transmit the use authorization for the contention time period to a
data transmission device using the TID information 431.
[0052] As an example, when the use authorization for the contention
time period transmitted using the TID information 431 corresponds
to "0," all data transmission devices may transmit data during the
contention time period.
[0053] When the use authorization for the contention time period
transmitted using the TID information 431 corresponds to "1," a
data transmission device having an order of priority greater than
or equal to "1" may transmit data during the contention time
period.
[0054] When the use authorization for the contention time period
transmitted using the TID information 431 corresponds to "2," a
data transmission device having an order of priority greater than
or equal to "2" may transmit data during the contention time
period.
[0055] When the use authorization for the contention time period
transmitted using the TID information 431 corresponds to "3," a
data transmission device having an order of priority greater than
or equal to "3" may transmit data during the contention time
period.
[0056] According to embodiments of the present invention, an order
of priority of each data transmission device may denote an access
category, and an order of priority of a data transmission device
may correspond to a value classified based on a traffic type, that
is, a characteristic of data transmitted by each data transmission
device, presented by QoS MAC of IEEE 802.11e. The traffic type
based on a characteristic of data transmitted by each data
transmission device will be further described with reference to
FIG. 6.
[0057] FIG. 5 is a diagram illustrating an allocation of a
contention time period according to embodiments of the present
invention.
[0058] Since a BI 510, a DTT 520, a BT 530, an A-BFT 540, an AT
550, and the like of FIG. 5 are similar to the BI 310, the DTT 320,
the BT 330, the A-BFT 340, the AT 350, and the like of FIG. 3,
further description will be omitted for conciseness.
[0059] Referring to FIG. 5, four contention time periods 560, 561,
562, and 563 are set in a DTT 520. Hereinafter, the contention time
periods 560, 561, 562, and 563 may be referred to as a first
contention time period 560, a second contention time period 561, a
third contention time period 562, and a fourth contention time
period 563, respectively for convenience of description. A TID
value in each of the contention time periods 560, 561, 562, and 563
indicates a use authorization of each of the contention time
periods 560, 561, 562, and 563.
[0060] Since a use authorization of the first contention time
period 560 corresponds to "0," all data transmission devices may
transmit data using the first contention time period 560. Thus, a
possibility of a data collision may be relatively high.
[0061] Since a use authorization of the second contention time
period 561 corresponds to "1," a data transmission device having an
order of priority greater than or equal to "1" may transmit data
using the second contention time period 561. Thus, a possibility of
a data collision may be slightly reduced.
[0062] Since a use authorization of the third contention time
period 562 corresponds to "2," a data transmission device having an
order of priority greater than or equal to "2" may transmit data
using the third contention time period 562. Thus, a possibility of
a data collision may be considerably reduced.
[0063] Since a use authorization of the fourth contention time
period 563 corresponds to "3," a data transmission device having an
order of priority greater than or equal to "3" may transmit data
using the fourth contention time period 563. Thus, a possibility of
a data collision may be significantly reduced.
[0064] FIG. 6 is a diagram illustrating a traffic mapping according
to embodiments of the present invention.
[0065] When data transferred from a higher level is transmitted
using a contention time period, a data transmission device may map
each data element to the corresponding access category with
reference to FIG. 6. Referring to FIG. 6, a value of an access
category may be determined as a priority of each data transmission
device.
[0066] Referring to FIG. 6, when data corresponds to a video probe,
the data may be mapped to an access category AC [1], and a priority
of a data transmission device may correspond to "1."
[0067] When data corresponds to a video, the data may be mapped to
an access category AC [2], and a priority of a data transmission
device may correspond to "2."
[0068] When data corresponds to a voice, the data may be mapped to
an access category AC [3], and a priority of a data transmission
device may correspond to "3."
[0069] A resource allocation device may set a use authorization for
a contention time period, and each data transmission device may
compare the use authorization and an order of priority of each data
transmission device, and may use a contention time period. Since a
portion of data transmission devices among all data transmission
devices may use a contention time period, a number of data
transmission devices using the contention time period may be
reduced. Thus, a possibility of a data collision may decrease in a
contention based transmission scheme.
[0070] As illustrated in FIG. 6, when a priority is determined
based on a characteristic of data, a data transmission device
transmitting audio data may set a highest priority for audio data.
Thus, a possibility of failing to transmit the audio data may be
significantly reduced.
[0071] FIG. 7 is a flowchart illustrating a method of transmitting
data according to embodiments of the present invention.
[0072] In operation 710, a data transmission device may set an
order of priority for a contention time period. According to
embodiments of the present invention, the data transmission device
may set the order of priority for the contention time period based
on a characteristic or a traffic type of data to be transmitted by
the data transmission device in a contention based transmission
scheme during the contention time period.
[0073] For example, when the data to be transmitted by the data
transmission device corresponds to audio data, the data
transmission device may set a relatively high order of priority for
the contention time period. When the data to be transmitted by the
data transmission device does not correspond to audio data, and
corresponds to video data, a downloaded file, and the like, the
data transmission device may set a relatively low order of priority
for the contention time period.
[0074] The data transmission device may set a relatively high order
of priority for the contention time period when data to be
transmitted is responsive to a time delay, and may set a relatively
low order of priority for the contention time period when data to
be transmitted is less responsive to a time delay.
[0075] FIG. 7 illustrates an example of setting an order of
priority based on a characteristic of data by the data transmission
device. According to another example, a resource allocation device
may determine an order of priority of the data transmission device,
and transmit the determined order of priority to the data
transmission device. The data transmission device may set an order
of priority for a contention time period based on the received
order of priority.
[0076] In operation 720, the data transmission device may receive,
from the resource allocation device, a use authorization for the
contention time period. The use authorization for the contention
time period may correspond to a value set by the resource
allocation device to limit a number of data transmission devices
using the contention time period.
[0077] In operation 730, the data transmission device may determine
whether to transmit data to a data reception device during the
contention time period with reference to the use authorization for
the contention time period. According to embodiments of the present
invention, the data transmission device may compare the order of
priority for the contention time period and the use authorization
for the contention time period, and may determine whether to
transmit data to the data reception device based on a result of the
comparison. For example, the data transmission device may determine
to transmit data using the contention time period when the order of
priority for the contention time period is greater than or equal to
the use authorization for the contention time period.
[0078] In operation 740, the data transmission device may transmit
data to the data reception device during the contention time period
according to a determination in operation 730. For example, the
data transmission device may wait during a predetermined period of
time from a starting time of the contention time period. When the
data transmission device receives second data transmitted by
another data transmission device during a predetermined period of
time, the data transmission device may determine that another data
transmission device transmits data during the contention time
period, and may cancel the transmitting of data of the data
transmission device.
[0079] When the data transmission device does not receive second
data transmitted by another data transmission device during a
predetermined period of time, the data transmission device may
transmit data to the data reception device during the contention
time period.
[0080] The data reception device may receive data from the data
transmission device, and may transmit, to the data transmission
device, a reception acknowledgement (ACK) message for the received
data.
[0081] In operation 750, the data transmission device may determine
whether the reception ACK message is received from the data
reception device. When a single data transmission device transmits
data, the data reception device may succeed in receiving the data,
and may transmit a reception ACK message to the data transmission
device. In this instance, the data transmission device may
terminate transmitting data.
[0082] When each of a plurality of data transmission devices
transmits data to the data reception device, a data collision may
occur. Thus, the data reception device may fail to receive any
data. When data fails to be transmitted, the data reception device
may not transmit a reception ACK message for the data to the data
transmission device. In this instance, the data transmission device
may determine the reception ACK message is not received in
operation 750. When the reception ACK message is not received, the
data transmission device may retransmit the data to the data
reception device in operation 760.
[0083] FIG. 8 is a flowchart illustrating a method of allocating a
resource according to embodiments of the present invention.
[0084] In operation 810, a resource allocation device may determine
a contention time period. According to embodiments of the present
invention, as illustrated in FIG. 5, the resource allocation device
may determine a plurality of contention time periods within the DTT
520 included in the BI 510.
[0085] In operation 820, the resource allocation device may set a
use authorization for the determined plurality of contention time
periods. According to embodiments of the present invention, the
resource allocation device may set the use authorization based on a
number of data transmission devices that receive the use
authorization from the resource allocation device.
[0086] For example, when the number of data transmission devices
that receive the use authorization from the resource allocation
device is relatively great, the resource allocation device may set
a use authorization for a contention time period to a relatively
high value, and may allow a data transmission device having a
relatively high order of priority to use the contention time
period.
[0087] In operation 830, the resource allocation device may
transmit the use authorization for the contention time period to a
plurality of data transmission devices.
[0088] According to an embodiment of the present invention, each
data transmission device may set an order of priority for a
contention time period. According to another embodiment of the
present invention, the resource allocation device may set an order
of priority of each data transmission device, and may transmit the
set order of priority to each data transmission device.
[0089] According to still another embodiment of the present
invention, the order of priority of each data transmission device
may be set based on a characteristic of data to be transmitted by
each data transmission device. The data transmission device may set
a relatively high order of priority when data to be transmitted is
responsive to a time delay, and may set a relatively low order of
priority when data to be transmitted is non-responsive to a time
delay. As the data sensitive to a time delay, audio data may be
given.
[0090] Each data transmission device may compare an order of
priority for each data transmission device and the use
authorization for a received contention time period, and may
determine whether to use the contention time period based on a
result of the determination.
[0091] For example, the data transmission device may determine to
transmit data using the contention time period when the order of
priority for the contention time period is greater than or equal to
the use authorization for the contention time period.
[0092] FIG. 9 is a flowchart illustrating a method of receiving
data according to embodiments of the present invention.
[0093] A data transmission device may compare an order of priority
set for a contention time period to an order of priority of the
data transmission device, and may transmit data to a data reception
device during the contention time period based on a result of the
comparison. For example, the data transmission device may determine
to use the contention time period when the order of priority of the
data transmission device is greater than or equal to the use
authorization for the contention time period, and may transmit data
during the contention time period.
[0094] In operation 910, the data reception device may receive data
from the data transmission device. According to an embodiment of
the present invention, the order of priority of the data
transmission device may be set based on a characteristic of data
transmitted by the data transmission device. When data transmitted
by the data transmission device is responsive to a time delay, for
example, when the data corresponds to audio data, the order of
priority of the data transmission device may be set to a relatively
high value.
[0095] According to another embodiment of the present invention,
each data transmission device may wait for a predetermined period
of time from a starting time of the contention time period. When
each data transmission device does not receive data from another
data transmission device during the predetermined period of time,
each data transmission device may determine that another data
transmission device fails to transmit data during the contention
time period. In this instance, a data transmission device may
transmit data to the data reception device.
[0096] In operation 920, the data reception device may determine
whether the data reception device succeeds in receiving data. For
example, when a single data transmission device transmits data in
operation 910, the data reception device may succeed in receiving
data. In this instance, in operation 930, the data reception device
may transmit a reception ACK message for the received data to the
data transmission device.
[0097] However, when a plurality of data transmission devices
transmits data in operation 910, data transmitted by the plurality
of data transmission devices may collide and thus, the data
reception device may not succeed in receiving data.
[0098] When the data reception device does not succeed in receiving
data, it may re-receive data in operation 940.
[0099] Operation 940 may be performed in a manner similar to
operation 910. When the data reception device receives data from a
plurality of data transmission devices in operation 910, the data
reception device may re-receive data in operation 940.
[0100] In operation 940, after a predetermined period of time from
a starting time of the contention time period for re-receiving
data, the data reception device may re-receive the data transmitted
in operation 910 by one of a plurality of data transmission devices
from another one of the plurality of data transmission devices
among the plurality of data transmission devices.
[0101] The above-described exemplary embodiments of the present
invention may be recorded in non-transitory computer-readable media
including program instructions to implement various operations
embodied by a computer. The media may also include, alone or in
combination with the program instructions, data files, data
structures, and the like. Examples of non-transitory
computer-readable media include magnetic media such as hard disks,
floppy disks, and magnetic tape; optical media such as CD ROM discs
and DVDs; magneto-optical media such as optical discs; and hardware
devices that are specially configured to store and perform program
instructions, such as read-only memory (ROM), random access memory
(RAM), flash memory, and the like. Examples of program instructions
include both machine code, such as produced by a compiler, and
files containing higher level code that may be executed by the
computer using an interpreter. The described hardware devices may
be configured to act as one or more software modules in order to
perform the operations of the above-described exemplary embodiments
of the present invention, or vice versa.
[0102] Although a few exemplary embodiments of the present
invention have been shown and described, the present invention is
not limited to the described exemplary embodiments. Instead, it
would be appreciated by those skilled in the art that changes may
be made to these exemplary embodiments without departing from the
principles and spirit of the invention, the scope of which is
defined by the claims and their equivalents.
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